Thermosetting foam products are prepared by the use of phenol-formaldehyde resin, blowing agents and strong acidic catalysts, and typically are characterized by having a fairly brittle foam structure, with low compression strength and exhibiting high friability and brittleness properties. Phenolic foams, which are acid-catalyzed, while often having acceptable properties, in that they are difficult to burn, melt or smoke, are characterized by having a substantially open-cell structure and very little, if any, strength at low density; for example, below about 2.5 pounds per cubic foot, a thermoconductivity similar to polystyrene foams, and having corrosion problems, due to the presence of the strong acid catalyst.
It is desirable to prepare rigid, thermosetting, strong, substantially closed-cell-type foam products exhibiting low density and with a substantially neutral pH, which foam products are characterized by good thermoconductivity approaching that of, or better than the, polyisocyanurates foams as well as having desirable heat and flame properties, such as foams, which will not substantially burn, smoke or melt.